Fluid-pressure-operated tool.



G. H. JOHNSON.

rum) PRESSURE 0211mm) TOOL.

2 SHEETS-SHEET 1.

$1.40 tfyfi.

Patented Jan. 18,1910.

LPPLIOATIOI I'ILED AUG. 16, 1905.

c. H. JOHNSON. FLUID PRESSURE OPERATED TOOL.

APPLICATION FILED AUG. 18, 1905.

Patented Jan.18,191C.

2 SKBBTB-8HEBT 2.

, mmnn STATES PATENT OFFICE.

CHARLES H. dOHNSON, OF SFRENGFIELD,

ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- .MENTS, TO THE PITTSBURG PNEUMATIC COMPANY, OF CANTON, OHIO, A. CORPORA- SIGN OF NEW JERSEY.

FLUID-PRESSUBE-OPEBATED TQOL.

Specification or Letters Patent. Patented J an. 18, 1910.

Application filed August 16, 1905. Serial No. 224,498.

To all whom it may COILCai'Ib.

Be it known that I,' CHARLES H. JOHN- soru acitizen of the United States, residing at Springfield, county of Sangamon, State of Illinois, have invented a certain new and useful Improvement in Fluld-Prcssure-Operated Tools, and declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it pert-ains'to make and use the same, reference being liad to the accompanying drawings, which form a part of this specification. My invention relates-1n eneral to fluid ressure operated tools and more particul rly to the type'of such tools commonly known as pneumatic hammers.

In the-operation of a )ncumatic hammer having a piston valve or controlling the supply and exhaust of compressed air'to and from the opposite ends of the cylinder,

the valve is usually reciprocated by air passing from the cylinder to the valve casing. In order that the piston may be moved from the front to the rear of the cylinder, it is necessary for compressed air to flow throu h a' passage uncovered by the piston slight y be ore reaching the limit of its forward 7 i Q stroke, to the valve casing to move the valve,

and for live air to flow through a passage leadin from the valve casing'to the front end 0 the cylinder. Owing to the lag in the movement of the valve and the distance the air must pass from the cylinder to the valve casing to throw the valve and from the valve casing to the front of the cylinder,

- the return movement. of the piston is slightly delayed and is accomplished entirely by live The primary. object of my invention is to provide a pneumatic tool in which the piston will be quickly moved from the front to the rear'of the cylinder and primarily by the ower of the air which drove the piston to tie front of the cylinder.

A further object of my invention is to provide a. fluid pressure operated tool in which the motive fluid which moves the piston toward the front of the cylinder will be stored in a reservoir and will be discharged therefrom to the front of the cylinder to impart an initial movement of the piston to ward the back end of the cylinder.

A. further'object of my invention is to provide a fluid pressure operated tool which will he comparatively. simple in construction and elficient in operation.

My invention will be more fully described hereina fter with reference to the accompanyingdrawings iu which the same is illustrated as embodied in a convenient and practical form, and in which- Figure 1 is a longitudinal vertical section; Fig. 2 an clevational view-of one side of the bushing, the cylinder being shownin section; Fig. 3 an elevational view of the opposite side of the bushing, the cylinder being also shown in section; Fig. 4 a sectional View on line 4-4 Fig. I on an enlarged scale; Fig. 5 a view-similar to Fig. 4; the-valve bcing shown in position. to admit, fluid pressure to the rear end of the cylinder; and Fig. 6 across sectional view on line 6-G Fig. 2'.

The same reference characters are used to indicate the some parts in the several figures of the drawings.

Reference letter A indicates the handle of the tool which is provided with a tubular extension A1surrounding the back end of the cylinder C. A lever A is pivotally supported in the handle A and is provided with :1 lug 11* adapted to eiwage the end of a valve stein .b*. The. throttle'valve is located within a-cylindrical valve casing 13 which is in screw threaded engagement with an opening B in the handle. A spring 13'' is interposed between the valve and the cylindrical valve casing and normally retains the valve in position to close the ports 5- formed through the valve seat. A passage B is formed in the handle A and is adapted to be connected witha conduit leading from a source of fluid pressure. The cylinder C is provided with a bushing-c one end of which is engaged by a cylinder head 0' which is secured within the end of the cylinder. The handle is retained upon the cylinder by mcans'of an annular flange A intcrhead and prevents the same from rotating with respect to the handle. The 'frontend of the cylinder isadaptcd to receive a snap ing the snap within the end of the cylinder,

such for instance as a ring it. seated within an annular groove formed in the. interior of the cylinder near the front end thereof.

'A cylindrical valve casing preferably formed integrally with the handle A, is located transversely beneath the back end of 'the cylinder. The valve casing is provided with a series of annular grooves with which communicate ports a, a", a and a registering wi h ports and passages leading to the interior of the bushing 1' so as to reciprocate the piston K therein. 'The port a communi- (rates with the passage (1' formed in the exterior of the cylinder and inclosed by the tubular extension A of the handle. The. passage 0' communicates through a hole -formed through the cylinder with a longitudina passage 0" formed in the exterior of the bushing c and communicating with the interior thereof at .a point located a slightly greater distance from the front end of the cylinderthan the length of the piston. The port a communicates with a hole through the cylinder C leading to a chamber C formed in the outer surface of the bushing. Ports 0 lead tronrthe chamber C" to-the interior of the bushing near the back end thereof. A plurality of ports are -prefcrably employed the front one of which 1s larger than the rear ones as clearly shown in Fig. 2. The port a. communicates with a hole through the cylinder leading to a port 0" extending through the bushing at a point adjacent the rear end-thereof. The port a communicates with a hole c through the cylinder and then with a passage C formed in the exterior of the bushing and extending to the front end of the cylinder. Supply ports aare located near the center of the valve casing and communicate with a passage A? formed in the handle A and extending from a point above the throttle valve.

The bushing E is located within the valve 1 casing A and is retained therein by means of the cap A which closes the open end of the valve casing. One end of the bushing is closed by means of a disk E while the other end of the bushing is provided with a concentric interior portion E which reduces the bore of the bushing. The bushing is provided within a series of ports a, e, e'-, e, e, 0'", which register with the corresponding ports a, m", a, a and a formed in the valve casing. A differential piston valve 1) is located within the bushing and controls the ports therethrough. The end I) of the valve is hollow and is provided with ports ti connecting an annular groove in the exterior surface'thereof with the hollow interior. A

ducing its diameter. An annular flange D oi; slightly greater diameter than t-he shonlder 1) is formed on the valve between such series of passages (Z extend through the valve and connect the annular space between the shoulder D and flange I) with an annular groove formed in the end I) of the valve. A restricted leakage port ol extends through the fiange'D.

may be readily assembled by inserting the valve in the bushing prior to placing the end cap E on the bushing and by then inserting the bushing with the valve thereof into the valve casing. The cap A may then be seing A The exterior of the bushing c is cut away to forin'longitudinal chambers F and F between the same and the cylinder C such chambers extending from points near the rear t'o points near the front of the bushing. ,A third chamber F is formed between the exterio of the bushing and the cylinder and extends om a point in advance of the chamber C to a oint near the front of the bushing. The members F, F and F communicate with the interior of the bushing through ports f, f and f at points located a distance from the front of the bushing slightly greater than the length of the piston. The chambers E, F and F also J0minunicate with the interior of the-bushing near the front end thereof by means of ports 7' and the ports f is less than the length of the piston in order that when the former ports are uncovered by the piston and the reservoirs charged, th pressure is prevented from passing back to the cylinder through the latterports. The chambers F, F and F constitute a reservoir in which motive fluid which moves the piston forwardly is stored and from which it passes to the front end of the bushing to drive the piston toward the back of the cylinder. The operation of my invention is as follows: The lever A is forced forwardly and thereby oscillated about its pivot so that the lug a thereon through the interposed valve stem depresses the throttle valve uncovering the ports [1 Fluid under pressure then flows from the Source thereof through the coupling B, thence through the ports I! to the passageway A. which communicates with center of the va ve casing 1i. 'hen the valve is in the position indicated in Fig. 5 fluid pressure flows from the supply port a through the ports a in the bushing. around the reduced portion of the valve. then through the ports a in the'bushing. the ports 0 thence to the chamber C through the first of the series of. ports 0 into the back end of the cylinder. is the piston successively unshoulder and the end I) of the valve.

The several parts bf the valve mechanism cured within the open end of the valve ens-- f. The distance between the ports f, f", and

the annular supply port alotated near the 5 \l'hen the valve is in the positionshoivn Fig: its ends are exposed to atmospheric py essure; D directly through poi-tea and ."through th front endof the cylinder by in" uvay of. portsand passages rl. e. a. c. L;

fcfginterior eibushing c, C 02 (1*. c and .while the'shoulder D and radial surfaces (1 Land 41*. are all exposed to the same pressure and. consequentlytlw valve is retained in this positionowing to the area of the radial surface (Z? being greater than the difference in area between the shoulder l) and the radial surface (13.. hen the piston has nearly reached the limit of its forward stroke theport ("'1 uncovered and fluid pressure then tiows through the passage communicating withsaid port to the port 1:. .thenee through theport o'in the valve casing. the ports :3 in the bushing. through the ports 1? to the hollow interior of the end 1) of the valve. The valve i consequently nioved from the position shown in- Fig. 3 I to that shownin i. This nu'ivement ot' the valve takes place owing to the area of 't-he end Df thereoi being greater than the 30 resultant area exp sed to pressure in the opposite direction. The valve is retained in such position by reason of the surface 17 being exposed to the atmosphere through the" Jportsand passages a c. 1- C111. 0 11' and (4 The surface being greater in area than the area of the shoulder Dathe valve is held in the position shown in Fig. i.

t hen the valve is in the position indicated in l ie the back end of the cylinder is 40 placed in communication with the exhaust through the following ports and passages: C 0 e", d and a. Fluid pressure is then admitted to thefront end of the cylinder to move the piston toward the handle through the following ports and passage I 6, d, P, (1*, and 1:, vhich communicates with pas age (3 leading to the front end of the cylinder. When the piston in its stroke away from the tool passes the series of 5Q ports 1' it is cushioned by the air compressed in tlie baelie'nd of the cylinder. The valve is moved from the position shown in Fig. 4 to fithat shown in 5 by fluid pressure passing through the restricted leakage port (I to i the opposite. side of the annular flange D Tivltere it is exerted upon the radial surface rifwhich is then no longer exposed to the ,ati nosphere a'sthe ports are closed by the piston and consequently as the area of the radial surface (2 is greater than the differeneefin giver-untranthi'dial surface (Z aiidllie shoulder D the valve is-moved to ;,t'he position shown-in Fig. 5 inasmuch as the V oppositeends of thi valve are exposed merely 63 'to atmospheric pressure dllQCil) through ports a. and a While a it 8.2 grooved is; shown me same may be omitted without interfering with the operation of the val'i'e as the leakage around the annular flange 11 15 sufiicient toeti'ert the reverse movement of the valve from the position sh wn in his:

to that shown in Fig. 5. k

lien the valve i; in the position shown in Fig. 3 the live air pa ses to the back of the cylinder. not only through the port k and eonnnunieating port but also around the annular flange l) which is of slightlv less diameter than the space within the bushing around the same. to the port 1 and thence through the port c". (-onstvpiently the piston i moved toward the front of the cvlinder by live air admitted through the port as; well as to the port V \Yhen the pi ton in its stroke tmvard the snap uncovers: the ports and 7'" motive fluid passes; o ti t re ervoir composed of the chambers F. l and F". lmnu-t'liatel} upon the piston striking the shank of the napit recoils sufiicicntly to cover the ports f. 7" and f and to uncover the ports f so that the 91'. motive fluid passes from the reservoir to the front of the cylinder and thereby imparts: to the piston an initial movement toward the hack of the cylinder. The completion of the movement of the piston away from the 95 tool is eii'ected by live air admittcl through the pas. e (3 a above described. The power deiived from the compressed air stored in the re ervoir however. sutlicient to not only impart to the piston an initial movemct'it, but to almost complete the back stroke of the piston thei'eby rendering it necessary to use only a sma l quantity of live air for the purpose of producing' the back stroke of the piston.

It will be noted by reference to Fig. 2 that theeontrol port 1" is uncovered by the. pi ton slightly before it uncovers the port leading to the reservoir chambers, but owing to the lag in the movement of the valve and the 1m rebound of the piston after striking the shank of the snap. the air passes to the reservoir chambers and is confined therein by the piston before the valve has moved into iosition to connect the rear end of the cylinder with the exhaust.

I do not in this application claim the differential valve shown in this application, as the same forms the subject matter of my copending application Serial X0. 131.949 filed November 19, 1902. I have merely illustrated such form of valve herein in order that niy'present improvement may be clearly understood.

T he invention which forms the subject of the claims of this east: is the storing of the motive fluid which drives the piston toward the front of the cylinder in a reservoir and utilizing the sameto drive the piston toward the back of the cylinder.

This invention'maycbviously be'us cd in connection with various forms of pneumatic tools. I do not therefore wishto be under: stood'as limiting my invention to use in connention with a pneumatic tool such as that herein illustrated and described.

Having noty fully described my irivent-ion what claini as new and desire to secure 'lgy Letters Patent is: Y

1. In a fluid pressure operated tool, the combination with a cylinder, oia reciprocat' in'g .piston within said cylinder, means foradm tting'fluid pressure nto one end of the cylinder to more the piston in one direction,- a rserioinfpr fluid pressure, means for connecting said reservoir with the opposite end -of the cylinder toimpart an initial movement to the pf. am in the opposite direction, and means forcoim'ecting the first mentioned end of the cylinder to atmosphere before the piston initial movement.

2. In a fluid pressure operated tool, the combination with a cylinccr, of a reciprocate ing isto'n within said cylinder, means for admitting-fluid pressure into one end of the cylinder to move thepist'on in one direction, a rwervoir for fluid pressure, means for charging said reservoir, means for connecting sai reservoir with the op ..'te end of, the cylinder to impart an initial movement to the piston in the opposite direction, and

means for connecting the first mentioned endnfthe cylinder to atmosphere before the piston begins said initial movement. 3.11; a fluid pressure operated tool. the combination with a cylinder. of a reciprocating piston within-said cylinder. means for admitting fluid pressure into one end of the cylinder to more the piston in one direction, a reservoir for fluid pressure, means forcharging said reservoir with fluid pressure from the aforesaid end of the cylinder durthe aforesaid movement of the piston,

means for connecting said reservoir wit the-- opposite end of the cylinder to impart an initial movement to the piston in the opposite direction, and means for connecting the first mentioned end of the cylinder to atmosphere before the piston begins said initial movement. 7 r

4. In a fluid pressure operated tool, the combination with a cylinder. of a reciprocating piston within said cylinder. a rsen'oir.

neans for chargingsaid reservoir with fluid '11ressure,means for connecting said reservoir with one end of the cylinder t im )art a movement to the piston. and means or admitting fluid pressure from a source thereofto complete the movement of the piston.

5. 111 a fluid pressure operated tool, the combination with a cylinder, of a reciprocating piston within said cylinder. a.reserroir. means for charging said reservoir with fluid pressure from ,the cylinder during the mov ment of the piston in one direction, means for connecting said reservoir with the cyl inder to-nnpart; a movementof thepistoi; iii

an oppo te direction,-ai1d'means or admitting fluid pressure from a source thereof t9 complete the gntwement of .the, piston in, said, direction. l

6. In a tinidpressure operated tool, the combination with a cylinder, of a reciprocat- .ing-pist-on'within said cylinder, a reservoir carried by said cylinder, said.cy1ind er hav 3 5 ing a port. leading to said reservoir slightly farther away from-one end of the cy11nder than the length of the piston and a second port leadin from said reservoir adjacent to said end 0 the cylinder, means for sup ly- 8o ing fluid pressure to the opposite end 0 -the cylinder to move the'piston in one direction and means for wnnecting the latter end ofthe cylinder to atmosphere after the piston pas completed its movement'in said diree- 7. In a fluid pressure operatedtool, the combination with a cylinder, of a reci n'ocab ing piston within and cylinder, a va ve for controlling the supply and exhaustof motive fluid to and from the opposite ends 'ofi sai'd cylinder, -a reservoir, means for charging said reservoir with fluid pressure from the cylinder during the movement of the piston in one direction, and means connecting said reservoir with said cylinder to impart a movement to the piston prior to the admission of fluid pressure through the valve to said end'of the cylinder.

8. In a fluid rcssure operated tool, the combination with a cylinder, of a reciprocating piston thereima valve for controlling 4 the supply and exhaust of motive fluid to and from the opposite ends of said cylinder,

a reservoir. means for charging said reservoir with fluid pressure from the cylinder during the movement of the piston toward the tool, and means for connecting said reservoir with the front end of said cylinder to impart a movement of the piston away no from the tool prior to the admission of fluid pressure through said valve tosaid end-of the cylinder.

9. In a fluid .ressnrc operated tool, the combination with a cylinder. of a recipn eating piston within said cylinder, said cylinder having longitudinal chamlx-rs formed therein and having ports controlled by said piston whereby pressure is admitted to the chambers from the cylinder and from the chambers to the cylinder to impart. a move- -ment to the iston away from the tool, and

ling the discharge of pressure controlling the admission of pressure to said reservoir from the cylinder and also controlfrom said reservoir to the front end of the cylinder to impart a movement of the piston away from the tool, and means for subsequently admitting fluid pressure from a source thereof to complete said movement of the piston.

11. In a fluid pressure operated tool, the

combination with a cylinder, of a reciprocating piston within said cylinder, a reservoir, means for charging said reservoir with fluid pressure, means for connecting said reservoir with one end of the cylinder to impart movement to the piston, and means for admitting fluid {pressure from a source thereof to said end 0. the cylinder.

12. In a fluid pressure operated tool, the combination with a cylinder, of a reciprocating piston Wi hin said cylinder, a reservoir, means for admitting compressed fluid to one end of said cylinder to move the piston in one direction, a reservoir, means for charging said reservoir when the piston approaches the end of its movement in the aforesaid direction, means for connecting said reservoir to the opposite end of the cylinder, and mea'ns for admitting fluid pressu're from the source thereoi to said latter end of the cylinder.

13. In a fluid pressure operated tool, the combination with a cylinder, of a reciprocating piston within said cylinder, means for admitting fluid pressure into one end of the cylinder to move the piston in one direction, a reservoir for fluid pressure, means for connecting said reservoir with the opposite end of the cylinder, and means for ex; hausting the one end of the cylinder when the other end is connected to said reservoir.

14. In a fluid pressure operated tool, the combination with a cylinder, of a reciproeating piston Within said cylinder, 2 reservoir, means for admitting fluid pressure in one end of said cylinder to move the piston in one direction, means for connecting said reservoir to the other end of the cylinder, and means for exhausting the first mentioned end of the cylinder.

In testimony whereof, I sign this speciiication in the presence of two witnesses.

CHARLES H. JOHNSON.

Witnesses:

Jnssm J. NETTLETQN, W. J. Aunnnros. 

